A coloboma is a hole in one of the eye structures, such as the iris. It can be present from birth (congenital) or the result of eye surgery or eye trauma. When congenital, it is caused by the failed or incomplete closure of the embryonic fissure, which normally closes around the 6th week of pregnancy.
Patients are more sensitive to glare since more scattered light can enter the eye through the “enlarged pupil”. Blue blocking filters can help counteract the effects.